摘要：It has long been recognized that the density of syntactic complexity is greater in written varieties of certain languages than in their spoken counterparts (Chafe 1985, Romaine 1992, Newmeyer 2002, Karlsson 2007, Mithun 2009, Laury and Ono 2010, and others). Such differences are not surprising: writers have the luxury of time to construct elaborate complex sentences, and readers the leisure to unpack them, while speakers and listeners must perform on the fly. Furthermore, writers must communicate without the benefit of prosody, a key dimension of speech, which can indicate much about the relationships between propositions. Writers are obligated to specify such relationships by other means, typically complex syntactic constructions. Some languages with uniquely oral traditions have been argued to lack syntactic complexity altogether, as seen in the recent flurry of discussion about Pirah. (Everett 2005, 2009, Nevins, Pesetsky, and Rogrigues 2009a,b, Sakel and Stapert 2010). Many languages without longstanding written traditions have recently borrowed conjunctions, complementizers, and relativizers from the European languages of colonizers, languages with deeply entrenched literary practices. Spanish loans of this type, for example, are particularly prominent in indigenous languages of Mesoamerica and South America. We know that structures developed within literary genres can enter the speech of writers, perhaps first in more formal registers. From there they might be passed on to other languages without writing through bilinguals. The effects need not be restricted to lexical loans. As illustrated by Johanson (2002), Heine and Kuteva (2006), Matras and Sakel (2007) and others, contact can affect grammar through grammatical replication or copying of structures from one language to another, even with no transfer of substance. These observations raise questions about how and why languages might differ in their distribution of information over sentences, in particular, in the forms, functions, and density of dependent clause constructions
